Where would I put an expense for a 2 month sublet at a secondary address?

If you are claiming employment expenses, you'll need to calculate the expenses for each location separately to get the correct amount you can claim. You can use the CRA's expense calculator to help you calculate the amount of expenses for each. Then add the amounts you calculated for each work space location together when filling in the lines on the form.

If you are claiming self-employment expenses, when it asks for “How many rooms in your home did you use for work?” and “How many rooms (total) are there in your home?” you can combine the sizes of the two places you lived, as well as the amounts of each expense. 

If you have TurboTax Live Assist & Review, see this TurboTax FAQ to learn how to talk to a Tax Expert or book a review: In TurboTax Live Assist & Review, how do I talk to a tax expert?